So I'm pricing and specing out a Bergara 6.5CM and I noticed that PSA has a standard Bergara 6.5CM barreled receiver for $606 while Brownell's has the Premier line  receiver w/ #5.5 profile barrel for $1050.  The one PSA has includes a trigger while the Brownell's does not.

Not knowing much of anything about Bergara's various lines, is the Premier version worth the +$450?  

I'm also looking at a Magpul folding stock chassis that DSA offers for $855.  For roughly that price range, is there another chassis I should be looking at?

I thought it was worth the extra money for the SS. I would be installing a Trigger Tech trigger regardless so that would not sway me one way or the other. You can’t go wrong either way.

The premier rifles can be found on sale for marginally more than the actions and would be a good choice and see how you like it.

If you are dead set on a chassis, I think the MPA complete builds are more bang for the buck than what you are describing. The magpul chassis doesn't seem like it has alot of traction in the market full of people where cost is no issue.

I have a 6.5C Premier LRP, before I bought I had been shooting my sons Tikka T3x TACT A1, shot a Christenson MPR and shot a Bergara B-14 BMP. The Tikka is a nice rifle, has nice feature but is heavy. I also didn't like the idea of having to use Tikka mags. The Christenson is a nice rifle but due to issues with hit or miss barrel accuracy I passed on it.
The Premier have a honed SS barrel, Trigger Tech trigger, the XLR chassis has nice features and the action is smooth and tight. The B-14 BMP is a nice rifle but when holding them side by side the Premier stood out as the better choice IMO.
What I found interesting is, when I took it to the range the first time the muzzle velocity was running 175-200FPS faster than my sons Tikka T3x TACT A1. Same barrel length, same twist and both shooting Hornady 147gr ELD Match, I attribute this to the honed barrel. The increased velocity really comes into play when shooting past 300yds, my son has to dope his scope more and more as the distance increases.

I've shot a R700 with the Magpul Chassis, IMO the Chassis isn't comfortable and lacking overall for the money the cost.

Same experience here. I was getting about 225 FPS more velocity than my friends RPR, both with 24” barrels, shooting my 140 gr. ELD-M handloads. I had my barrel cut to 20” and I still get 20-25 FPS more velocity than he does with his 24” barrel.

OP, I was debating this just a few months ago. I decided against both. Because you can get a custom action and shouldered prefit barrel for just a little bit more. Specifically a big horn origin action $875 and a proof Research steel prefit for around 500 or less if you qualify to the mil/le discount on expertvoice. The big benefit with this is you can swap barrel at home and if you ever shot the barrel out you can just buy a new one and have it shipped to you front door. This way you don’t have to send the action to bergara and Wait for them to rebarrel it. Also the custom actions hold their value really well.

At what point will you be happy with accuracy?
The Bergara rifles have a pretty good reputation for what price point they are at.
I just did exactly what the poster above me suggested.  I don’t qualify for any discounts so it’s more like a $1600 type of investment for a Orgin with Proof prefit.

You really can’t go wrong at the various price points.  Premier version with trigger seems like a very attractive option if your round counts will not require yearly barrel swaps.